The clashes between the SPLA and fighters loyal to rebel leader George Athor have broken out in three states.
After similar clashes last week, the southern government accused the north and President Omar al-Bashir of trying to destabilize it.
“The fighting was very heavy, but the rebels are now being pursued,” said SPLA spokesman Philip Aguer, reports the AFP news agency.
The fighting left 34 SPLA soldiers and 36 rebels had been killed.
Recently, Associated press (AP) reported former U.S. President Jimmy Carter’s democracy rights group, saying, “Southern Sudan’s ruling party risks future conflict in its oil-rich territory if it doesn’t include opposition parties in decisions during the run-up to its July independence declaration”.
The Carter Center said, “distrust between the ruling Sudan People’s Liberation Movement, or SPLM, and opposition parties is a critical challenge that “undermines the unity of Southern Sudan on the eve of its independence.”
The Carter Center warned that the south’s ruling party was failing to uphold its commitments to include opposition parties in key aspects of the region’s political transition, including the review of its interim constitution.
“The way in which the south’s ruling party handles the current period will be indicative of its overall attitudes toward governance and democracy in the new country of Southern Sudan,” said Maggie Ray, who leads the Center’s observation mission in the south.
“There is reason for concern with the SPLM’s approach to date,” Ray told The Associated Press, citing anger among southern opposition leaders at the way the ruling party has handled the interim constitution process.
Pagan Amum, the secretary general of the SPLM, said: “The SPLM believes that the future of Southern Sudan lies in building a multiparty democracy based on respect for and guarantees of basic freedoms and human rights.”
South Sudan is due to declare independence in July, following decades of north-south conflict.
Some 99% of South Sudanese voters backed secession in January’s referendum, which was part of a 2005 peace deal.